Kaspersky: Protection wise, Kaspersky is the clear winner, not even when talking about static detection. The behavioral and application control modules in Kaspersky are incredibly strong; even if something were to get past the heuristics (which are also one of the best), the application control of KAV/KIS will limit what said malware could do... unless of course it was digitally signed using a fake certificate. Kaspersky automatically gives full trust to digitally signed items on default settings (unless that has changed). If you (or anyone for that matter) use(s) KAV/KIS I highly recommend going into the application control settings and unchecking the setting to fully trust signed applications. Kaspersky's firewall is also one of the best when it comes to automatically controlling internet access for programs; rare is the occasion when you have to decide yourself to let a program connect or not (again, recommend unchecking the "automatically trust digitally signed programs" option).
Now, the reason I cannot use Kaspersky is because it makes my system completely unusable. I have tried time and time again when a new version is released (as to not be one of those people who only try it once and say "XYZ Product sucks because it is slow and bloated.... when that was 10 years ago). Each time, my system slows to a complete crawl. The User Interface of Kaspersky takes a good while to load, and the system responsiveness overall drops severely, and often locks up completely when I try to simply open a web browser. Mind you I have 16 GB of RAM, an Intel i7 4510U and an SSD... my computer is not exactly lacking in the power department. This is my biggest issue with Kaspersky.
Avast: avast isn't as good in detection as Kaspersky, but as we know here in MT and as it's been said time and time again, detection isn't everything
. Avast is certainly lighter than Kaspersky, unless you tell the filesystem shield to scan
all files
any time they are modified, written, read, and opened, scan whole files... then your system will become just a paperweight, because that's all you'll be able to use it for, but who really needs to set the filesystem shield to do that anyway? Scanning on writing and opening, for the most part, covers the file enough in regards to realtime scanning. There comes a point where scanning the file 5 times in a 5 second time span won't really accomplish much.... so if you leave the default settings for the scanning portion of the filesystem shield, you should be fine; however I would recommend that in the filesystem shield settings you increase the heuristics to maximum. Avast's firewall also auto-decides internet access for applications, and I can't speak as to which firewall is smarter (avast or KIS) as I haven't put the two of them against each other in a dedicated test. Avast IS includes a sandbox, which you can use to run files you aren't sure about, or just to sandbox your browser. Kaspersky does not include a sandbox.
Avast also includes "Home Network Security" which scans your router to make sure it is set up properly (according to the avast website). Kaspersky also does not include this type of module.
Biggest issues with avast!: constant up selling of other avast products... look, I already purchased your full version IS/Premier... I don't need you trying to get me to drop another 50$ on secureline, or password manager, or grimefighter.... I purchased an AV Suite, not an avast advertisement suite. Although you can disable the nag screen popups in the paid versions, they shouldn't even be there in the first place.
The other
major problem I have with avast is that tech support cost 180& A YEAR!! Almost ALL paid security solutions include free support.... 180$ is extremely expensive... it costs more than the product itself!!!
Both AIS and KIS include some sort of secure browser or banking protecting, again I can't speak for which is better as I haven't tested them 1v1 specifically. They work a bit differently, as AIS uses an isolated/virtualized browser known as "SafeZone", but honestly, if the end result is the same: protect your banking/sensitive data from keyloggers, MiTM, screen capture, etc. then they are even in my book even if AIS's SafeZone works differently from KIS's banking protection.
Honestly, I didn't yet vote for either product, because I personally use neither of them exclusively... I enjoy playing around with them and exploring them, but I don't rely on either of them. If I had to choose between the two of them in regards to giving a recommendation, I would probably say Kaspersky... IF your system doesn't lock up when you try to use it.